From: Chris Lattner <sabre@nondot.org>
Date: Fri, 6 Nov 2009 23:19:58 +0000 (+0000)
Subject: Fix a bug where we'd call SplitBlockPredecessors with a pred in the
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=79f0332c203b33c4afc0fb6ad946fbe041164e6e;p=oota-llvm.git

Fix a bug where we'd call SplitBlockPredecessors with a pred in the
set only once even if it has multiple edges to BB.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86299 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index 62f7d51ff8c..4bbde1397c8 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -940,8 +940,17 @@ bool JumpThreading::ProcessThreadableEdges(Instruction *CondInst,
   // predecessors that will jump to it into a single predecessor.
   SmallVector<BasicBlock*, 16> PredsToFactor;
   for (unsigned i = 0, e = PredToDestList.size(); i != e; ++i)
-    if (PredToDestList[i].second == MostPopularDest)
-      PredsToFactor.push_back(PredToDestList[i].first);
+    if (PredToDestList[i].second == MostPopularDest) {
+      BasicBlock *Pred = PredToDestList[i].first;
+      
+      // This predecessor may be a switch or something else that has multiple
+      // edges to the block.  Factor each of these edges by listing them
+      // according to # occurrences in PredsToFactor.
+      TerminatorInst *PredTI = Pred->getTerminator();
+      for (unsigned i = 0, e = PredTI->getNumSuccessors(); i != e; ++i)
+        if (PredTI->getSuccessor(i) == BB)
+          PredsToFactor.push_back(Pred);
+    }
 
   BasicBlock *PredToThread;
   if (PredsToFactor.size() == 1)